It has been a long known practice to ventilate attics under gable roofs by the use of soffit ventilators. Soffit ventilators are perforated or louvered vent openings in the underside, or soffit, of the eaves of an overhanging roof. The vents allow fresh ambient air to flow into the attic to equalize interior temperature and pressure with the outside. This equalization inhibits moisture from condensing on insulation and wood roofing materials, prevents buildup of ice dams which could buckle shingles and gutters, and reduces air-conditioning costs when hot attic air is replaced by cooler ambient air.
A soffit ventilator system may work in conjunction with a passive roof vent, such as a ridge vent, or with a forced-air fan to provide positive ventilation. As hot stale air is withdrawn through the roof vent by convection, wind suction, and/or forced flow, it is replaced by fresh ambient air through the soffit vents.
However, in construction where there is no soffit or a very narrow soffit with no vent openings, or the use of a soffit vent would adversely affect the building's exterior appearance which outweighs the benefit of installing vent openings, for example a historic building, an alternative method is required.
It is thus desired to have a roof construction that allows for ventilation and fresh air flow through the attic without the need for a soffit or cutting vent holes into a soffit.